High content Er3+ doped ZBLAN glass: The spectral characteristics and high slope efficiency MIR laser investigation.

• The high content (6.0 mol%) Er3+ ions doped ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF (ZBLAN) fluoride glass sample with low OH- concentration (0.013 cm−1) was prepared. • The radiative trapping effect of Er3+ ions with different sample size has been investigated. • The numerical modeling results showed the mid-infrared output-laser improved greatly and even exceeded the Stokes limit. The influence of radiation trapping effect on the fluorescence and decay of the heavy concentration Er3+ doped ZBALN glass were investigated, and numerical simulation proves that high-slope efficiency 2.7 µm laser output can be achieved. ga1 The ZBLAN glass with high content of Er3+ was prepared and studied. The glass has a wide infrared transmittance range of 2.5–8.0 µm, which means a lower maximum phonon energy. By testing and analyzing the fluorescence spectrum and lifetime curves under different penetration depths, the intrinsic emission spectrum and lifetime of the sample are obtained without the influence of sub-absorption. Under 980 nm excitation, the maximum emission cross section and the lifetime of 2.7 µm are 6.10 × 10−21 cm2 and 6.49 ms, indicating that high-concentration doping has a larger laser quality factor. According to the rate equation and transmission equation, cascaded and non-cascaded fiber laser models are established to conduct research on 2.7 µm fiber lasers. The slope efficiency can reach 40.38% at a pump wavelength of 980 nm and a fiber background loss of 0.1 dB/m. The high emission cross section, long fluorescence lifetime and high slope efficiency output make ZBLAN glass heavily doped with Er3+ an ideal host material for mid-infrared lasers. [ABSTRACT FROM AUTHOR]